(a) Field of the Invention
The present invention relates to a functional agent for decomposing nicotine and method of preparing the same, and more specifically a functional agent that removes the harmfulness of nicotine caused by smoking and can inhibit the generation of carcinogen caused by smoking.
(b) Description of the Related Art
Nicotine is colorless or a light yellow poisonous liquid that is absorbed into a body by smoking. Nicotine is so poisonous that it affects the cellular membrane of nerve ganglion. In addition, nicotine is known as causing an increase in blood pressure, convulsion of skeletal muscle fiber, and mouth paralysis due to excitation.
Instant harmfulness of nicotine includes contraction of the pupil, eye sight opacity, vomit, nausea, stomach ache, diarrhea, difficulty in controlling urination, laryngeal burn, difficulty in breathing, increase of secretion in salvia and a respiratory organ, blue disease, and decrease of pulse beat. When smoking is prolonged, nicotine is accumulated in a body so that it can cause cancer, hypertension, mouth disease, various gastrointestinal disorders due to excessive acid dyspepsia, and various circulatory diseases such as arteriosclerosis. Also, nicotine is an important factor in facilitating aging and in severe cases, it causes spasms, convulsion, breathing paralysis, muscle convulsion, and unnecessary hypertension (Damaj, M. I., Welch, S. P. and Martin, B. R. (1996) J. Pharmacol. Exp. Thr., 277 454–461).
Nicotine acts as a very strong carcinogen by nicotine-derived nitrosamine. There are hundreds of million of patients suffering from lung cancer and lung diseases caused by smoking all over the world every year. In 1956, Magee and Barnes proved that N′-nitrosodimethyl amine (NDMA) is a very strong liver cancer-inducing material in rats (Magee, P. N., and Barnes, J. M. (1956) Br. J. Cancer, 10. 114–122) and thereafter over 30 species of N-nitrosamine compounds are confirmed as having carcinogen-activity (Druckrey, H., Preussmann, R., Ivankovic, S., and Schmahl, D. (1967) Z. Krebsforsch., 69, 103–201 ; Preussmann, R., and Stewart, B. W. (1984) N-nitroso carcinogens. In Chemical Carcinogenesis, (Searle, C. E., Ed.) pp 643–828, American Chemical Society, Washington, DC. ; Lijinsky, W. (1992) Chemistry and Biology of N-Nitroso Compounds, Cambridge University Press, Cambridge, England.; Bogovski, P., and Bogovski, S. (1981) Int. J. Cancer, 27, 471–474).
In 1962, Druckrey and Preussmann suggested that nitrosamine which was derived from alkaloid of tobacco existed in tobacco smoke(Druckrey, H., and Preussmann, R. (1962) Die Natur., 49, 488–499). In 1964, Boyland et al confirmed that NNN(N′-nitrosonornicotine) occurs a lung cancer in mouse and NAB(N′-nitrosoanabasine) occurs cancer of the esophagus in rats (Boyland, E., Roe, F. J. C., and Gorrod, J. W. (1964) Nature, 202, 1126; Boyland, E., Roe, F. J. C., and Gorrod, J. W., and Mitchley, B. C. V. (1964) Br. J. Cancer, 18, 265–270).
Smith et al proved that various nitrosamine is generated from nicotine in his classical research (Smith, P. A. S., and Loeppky, R. N. (1967) J. Am. Chem. Soc., 89, 1148–1152) based on nitrosation of tertiary amine via iminium ion (Klus, H., and Kuhn, H. (1975) Fachliche MittAustria Tabakwerke, 16, 307–317; Hecht, S. S., Chen, C. B., Dong, M., Ornaf, R. M., Hoffmann, D., and Tso, T. C. (1977) Beitr. Tabakforsch., 9, 1–6). Hecht et al confirmed that 4-(methylnitrosamino)-1-(3-pyridyl)-1-1-butanone (NNK), 4-(methylnitrosamino)-4-(3-pyridyl)-butanal(NNA), NNN and other nitro compounds are generated from nicotine and detected NNK from tobacco (Hecht, S. S., Chen, C. B., and Hoffmann, D. (1976) Tetrahedron Lett., 8, 593–596; Hecht, S. S., Chen, C. B., Ornaf, R. M., Jacobs, E., Adams, J. D., and Hoffmann, D. (1978) J. Org. Chem., 43, 72–76; Hecht, S. S., Chen, C. B., Hirota, N., Ornaf, R. M., Tso, T. C., and Hoffmann, D. (1978) J. Natl. Cancer Inst., 60, 819–824).
FIG. 1 shows various nitrosamines metabolized from nicotine.
Until now, seven tobacco-specific nitrosamines such as NNN, NNK, NNAL, NAT, NAB, iso-NNAN and iso-NNAC were identified from products of tobacco and NNN, NNK, and NAT were detected in larger amount than others. Particularly, NNN, NNK, and NNAL have already been confirmed as very strong carcinogens.
Nicotine is metabolized to cotinine through two processes and cytochrome P450 (hereinafter, CYP) and cytosol aldehyde oxygenase are involved on the metabolism. Nicotine is metabolized to cotinine by various CYPs, and CYP 2A6 has an important role (Cashman, J. R., Park, S. B., Yang, Z. C., Wrighton, S. A., Jacob. P. III., and Benowitz, N. L. (1992) Chem. Res. Toxicol., 5, 639–646).
FIG. 2 shows the metabolism of nicotine to cotinine.
70 to 80% of nicotine is conversed into cotinine and 10 to 15% of cotinine is excreted as urine and the remainder is metabolized to ketoic acid. 85% of ketoic acid is metabolized to hydroxy acid and excreted as urine. 4% of nicotine that is not metabolized to cotinine is conversed into nicotine-1-N-oxide by FMO (flavin-containing monooxygenase) and most is excreted as urine (Benowitz, N. L., Jacob. P. III., and Fong, I. (1994) J. Pharmacol. Exp. Ther., 268, 296–301). Therefore, 80 to 90% of nicotine is excreted as urine through metabolism (Kyerematen, G. A., Morgan, M. L., Chattopadhyay, B., deBethizy, J. D., and Vessel, E. S. (1990) Clin. Pharmacol. Ther., 48, 641–651; Caldwell, W. S., Greene, J. M., Byrd, G. D., Chang, K-M, Uhrig, M. S., deBethizy, J. D., Crooks, P. A., Bhatti, B. S., and Riggs, R. M. (1992) Chem. Res. Toxicol., 5, 280–285 ; Byrd, G. D., Chang, K-M., Greene, J. M., deBethizy, J. D. (1992) Drug. Metab. Dispos., 20, 192–197 ; Jacob. P. III., Benowitz, N. L., and Shulgin, A. J. (1988) Pharmacol. Biochem. Behav., 30, 249–253).
As shown in FIG. 3, NNK is a pro-carcinogen to laboratory animals and is mainly metabolized in the liver and the lung by CYP enzyme. The main step of NNK activation is α-hydroxylation mediated by CYP and in the reaction, NNK converts to methyl-diazohydroxide which is an unstable metabolite and it gives methyl group to DNA and generates O6MeG. O6MeG has been used as a promutagenic biological index for carcinogen derived from NNK.
It was reported that CYP is related to α-hydroxylation of NNK and NNN in A/J mouse, induces methylation of DNA, and forms O6-methylguanine(O6MeG) so that GC->AT transitional mispairing occurs and it activates K-ras proto-oncogene (Brown, B. G., Ching-jey, G. C, Paul, H. A., Chin, K. L., and David, J. D. (1999) Toxicol Scien., 47, 33–39).
Therefore, it was suggested that lung cancer caused by NNK through CYP could be effectively inhibited by using a substrate competitive inhibitor against substrate of CYP enzyme such as nicotine or cotinine in vitro or in vivo because it inhibits the activation of NNK metabolism(α-hydroxylation)(Brunnemann, K. D., et al. (1991) Crit Rev Toxicol., 21(4), 235–40). FIG. 4 shows structural similarity between NNN, nicotine, and NNK that are related to the metabolism of cytochrome P450 2A6.
Cotinine that is a main metabolite of nicotine, and ketoic acid and hydroxyl acid that are metabolite thereafter, are rapidly metabolized and excreted as urine. This metabolism has variation according to people. Cotinine, ketoic acid and hydroxyl acid are only factors affected by smoking, not a carcinogen. Furthermore, they act as competitive inhibitors to inhibit tobacco-specific nitrosamine converting carcinogen through CYP existing in the liver. Therefore, nicotine that is rapidly metabolized to cotinine, can reduce the harmfulness of smoking and inhibit cancer more effectively than nicotine that converts to derivatives such as NNK, NNA and NNN.